This invention relates generally to method and apparatus useful in building construction, and specifically to such method and apparatus which provide for the connection an end of a horizontal beam to a vertical surface of supporting structure.
The invention to be described herein is directed primarily to the construction of the basic framework of a building. Usually, at least in the commercial building trade, a strong support skeleton is erected to which the floors, walls, siding, etc. are affixed for the completion of a usable structure. Modern support skeletons normally include steel, concrete, or a combination of the two; however, other suitable construction materials are from time to time employed. No matter what specific materials are employed, the rudimentary erection process involves the placement of vertical elements with horizontal elements affixed therebetween for stability.
The prior art has employed a vast number of varying techniques to accomplish skeletal erection. For example, if the construction is to comprise steel columns and beams, the columns are first properly fixed in position and the beam are raised, by crane, to the horizontal position and held there while bolts or rivets are affixed through aligned holes in the flanges of the columns and beams. This process is quite time consuming inasmuch as the number of suitable cranes on any one construction site is very limited, and the fixing procedure must be accomplished by hand while the crane is holding the beam in position. Sometimes, instead of using mechanical fixing means such as bolts or rivets, the beams are welded to the columns. This procedure, too, is very time consuming.
In most precast concrete skeletal structures, the beams, or horizontal elements are generally supported on a horizontal surface of a concrete corbel projecting from the face of a column, or vertical element. Bolting or welding is generally required to complete such connections; and where grout is also required, special external formwork for the grout must be individually fashioned at each joint.
The prior art reveals a wide variety of such connections as each engineer designs the connection for each particular application.
The known prior art connection apparatus and methods are even further difficult to employ because they do not conveniently accomodate ordinary dimensional deviations from planned beam lengths. All concrete structures, including precast concrete beams, shorten as the concrete hardens. The shortening characteristic of concrete beams is not precisely predictable and requires, therefore, some tolerance or accomodation of small deviations from the planned length of a beam. Also, it is necessary to provide some accomodation of ordinary small deviations with regard to the planned position of the supporting column. A need, therefore, exists for an apparatus and method for connecting a beam to a vertical surface of supporting structure which are uniform and easily adapted for specific applications, which do not require welding at the site, which reduce the amount of time required to position and secure the beam, which provide confined spaces for grout within the connection, and which will accomodate ordinary deviations from the planned length of beams and from the planned position of the supporting structure. The present invention is directed to that need.